Power drive assistant system for bicycle

ABSTRACT

A power drive assistant system includes a wheel mover detachably fastened to the seat tube of a bicycle and holding an external rotor motor in friction contact with the rear wheel of the bicycle and controllable to rotate the rear wheel of the bicycle by means of a friction force, a rechargeable battery pack mounted on the seat pillar of the saddle of the bicycle to provide the external rotor motor of the wheel mover with the necessary working voltage, and a speed controller mounted on the handlebars of the bicycle for regulating the speed of the external rotor motor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to bicycles and more particularly, to apower drive assistant system for easy installation in a bicycle torotate the rear wheel by means of a friction force subject to theoperation of a battery-operated motor rotor.

2. Description of the Related Art

Following the growing awareness of environmental protection concept andthe growing of energy crisis, bicycle has been intensively used bypeople as one's personal transportable vehicle for the purpose ofexercise. Using a bicycle as one's personal transportable vehicleinstead of a motorcycle or car effectively achieves energy saving andcarbon reduction. Many bicycles are made foldable for carrying by a userwho is taking a mass transportable vehicle. There are bicycles equippedwith a power drive assistant system to assist the user reduce physicalload.

However conventional power drive assistant systems for bicycle are stillnot satisfactory in function and have drawbacks as follows:

1. Conventional power drive assistant systems for bicycle are not DIY(do-it-yourself) designs, not practical for installation by users.

2. During operation of the motor of a conventional power drive assistantsystem in a bicycle, the pedals of the bicycle are rotated, causingdanger.

3. During rotation of the gears and chain of a conventional power driveassistant system in a bicycle, a high level of noise will be produced.

Therefore, it is desirable to provide a power drive assistant system forbicycle that eliminates the aforesaid drawbacks.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances inview. It is one object of the present invention to provide a power driveassistant system for bicycle, which has light weight, small size and DIYdesign characteristics. It is another object of the present invention toprovide a power drive assistant system for bicycle, which is practicalfor installation in any of a variety of bicycles by a user conveniently.It is still another object of the present invention to provide a powerdrive assistant system for bicycle, which combines a motor and a batteryto assist the bicycle for short-distance and local-area application,satisfying the requirements for energy saving and carbon reduction.

To achieve these and other objects of the present invention, a powerdrive assistant system comprises a wheel mover mounted on the seat tubeof a bicycle, a rechargeable battery pack mounted on the bicycle andadapted for providing the necessary working voltage to the wheel mover,and a speed controller for controlling the speed of the wheel mover. Thewheel mover comprises a motor holder holding a motor, for example,external rotor motor that can be moved into friction contact with therear wheel of the bicycle and then controlled to rotate the rear wheelof the bicycle, a rotary shaft movably coupled to the motor holder, anda clamp pivotally connected to the rotary shaft for fastening the rotaryshaft to the seat tube of the bicycle.

Further, a clutch structure is coupled between the rotary shaft and theclamp for allowing elevational adjustment of the rotary shaft relativeto the clamp to move the external rotor motor into friction engagementwith the rear wheel of the bicycle or away from the rear wheel of thebicycle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a power drive assistant system installed in a bicycleaccording to the present invention.

FIG. 2 is an enlarged view of a part of FIG. 1.

FIG. 3 is an elevational view of the wheel mover of the power driveassistant system according to the present invention.

FIG. 4 is a top view of FIG. 3.

FIG. 5 is a side view of FIG. 3.

FIG. 6 corresponds to FIG. 5, showing the arrangement of the clutchstructure between the rotary shaft and the clamp.

FIG. 7 is an enlarged view of a part of FIG. 6.

FIG. 8A illustrates an operation status of the clutch structure of thepower drive assistant system according to the present invention.

FIG. 8B illustrates another operation status of the clutch structure ofthe power drive assistant system according to the present invention.

FIG. 9A illustrates the rotary shaft of the wheel mover in the highposition according to the present invention.

FIG. 9B illustrates the rotary shaft of the wheel mover in the lowposition according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, a power drive assistant system used in abicycle 10 in accordance with the present invention is shown comprisinga wheel mover 20, a rechargeable battery pack 30 and a speed controller40.

The wheel mover 20 is affixed to the seat tube 11 of the bicycle 10. Therechargeable battery pack 30 is affixed to the seat pillar of the saddleof the bicycle 10 by means of a clamp 31 and fastening belt 32. Further,the speed controller 40 is installed in the handlebar of the bicycle 10.

Referring to FIGS. 3˜5, the wheel mover 20 comprises a rotary shaft 27,a motor holder 25, and a clamp 21.

The clamp 21 is formed of a fixed jaw and a movable jaw and pivotallyconnected to one end of the rotary shaft 27, defining a clamping mouth211 between the fixed jaw and the movable jaw for receiving the seattube 11 of the bicycle 10. A locking pin 22 is pivotally connected tothe free end of the fixed jaw of the clamp 21. An operating handle 221is pivotally connected to the free end of the locking pin 22 andoperable to secure the free end of the locking pin 22 to the free end ofthe movable jaw of the clamp 21 and to further lock the clamp 21 to theseat tube 11 of the bicycle 10.

The rotary shaft 27 is coupled to the motor holder 25. A spring member28 is sleeved onto the rotary shaft 27 and stopped against the frontside of the motor holder 25. An adjustment nut 26 threaded onto therotary shaft 27 and stopped against one end of the spring member 28opposite to the motor holder 25 and rotatable relative to the rotaryshaft 27 to adjust the spring force of the spring member 28. A lock nut261 is mounted on the rear end of the rotary shaft 27 at the rear sideof the motor holder 25 and rotatable to lock the rotary shaft 27 to themotor holder 25. Further, a motor 29 is mounted in the motor holder 25at the bottom side and electrically connected to the rechargeablebattery pack 30. Further, the motor 29 according to the presentpreferred embodiment is an external rotor motor for rotating the realwheel of the bicycle 10 by means of a friction force.

Referring to FIGS. 6, 7, 8, 9A and 9B, a clutch structure is providedbetween the clamp 21 and the rotary shaft 27 for allowing adjustment ofthe elevation of the rotary shaft 27 relative to the clamp 21 to movethe motor 29 toward or away from the rear wheel of the bicycle 10between a low position (see FIG. 9A) and a high position (see FIG. 9B).

The clutch structure comprises a rectangular bar 231 transverselydisposed at the rear side of the clamp 21, a gear 23 fixedly mounted onthe rectangular bar 231, two spring members 273 mounted in the frontside of the rotary shaft 27 adjacent to the gear 23, two pawls 272respectively supported on the spring members 273, a clutch lever 24pivotally connected to the front side of the rotary shaft 27, and a cam271 fixedly mounted on one end of the lever 24 and stopped between thepawls 272 (see FIG. 7).

When wishing to lower the rotary shaft 27 and the motor holder 25 withthe motor 29 to the low position (see FIG. 8A and FIG. 9A), move theclutch lever 24 to the left side to force the cam 271 against theleft-sided pawl 272 and to further move the left-sided pawl 272 awayfrom the gear 23, and then lower the rotary shaft 27 and the motorholder 25 relative to the clamp 21, forcing the motor 29 into contactwith the rear wheel of the bicycle 10. On the contrary, when wishing tolift the rotary shaft 27 and the motor holder 25 with the motor 29 tothe high position (see FIG. 8B and FIG. 9B), move the clutch lever 24 tothe right side to force the cam 271 against the right-sided pawl 272 andto further move the right-sided pawl 272 away from the gear 23, and thenlift the rotary shaft 27 and the motor holder 25 relative to the clamp21, disengaging the motor 29 from the rear wheel of the bicycle 10. Whenmoving one pawl 272 away from the gear 23, a clicking sound will beproduced.

Further, the motor 29 is electrically connected to the rechargeablebattery pack 30 by a power cord 33 (see FIG. 5). Thus, the rechargeablebattery pack 30 provides the motor 29 with the necessary workingvoltage. Further, the speed controller 40 is affixed to the handlebar ofthe bicycle 10 and electrically connected to the rechargeable batterypack 30 and the external rotor motor 29 for controlling the speed of theexternal rotor motor 29.

Thus, the bicycle 10 is practical for use by a salary man/woman orranger for short-distance and local area application. When the user isnot going to use the power drive assistant system, the user can adjustthe elevation of the rotary shaft 27 relative to the clamp 21 to liftthe motor 29 away from the rear wheel of the bicycle 10.

Although a particular embodiment of the invention has been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention. Accordingly, the invention is not to be limited except asby the appended claims.

1. A power drive assistant system installed in a bicycle to assistrunning, the power drive assistant system comprising a wheel moveraffixed to the seat tube of the bicycle and adapted for rotating therear wheel of the bicycle, a rechargeable battery pack fixedly mountedon the seat pillar of the saddle of the bicycle to provide said wheelmover with the necessary working voltage, and a speed controllerinstalled in the handlebar of the bicycle for controlling the operationspeed of said wheel mover, wherein said wheel mover comprises: a motorholder; a motor mounted in said motor holder and movable with said motorholder into friction contact with the rear wheel of the bicycle androtatable to move the rear wheel of the bicycle by means of a frictionforce; a rotary shaft rotatably coupled to said motor holder; a springmember sleeved onto said rotary shaft and stopped against a front sideof said motor holder; an adjustment nut threaded onto said rotary shaftand stopped against one end of said spring member opposite to said motorholder; a lock nut threaded onto said rotary shaft and stopped at a rearside of said motor holder and adapted for locking said rotary shaft tosaid motor holder; and a clamp coupled to one end of said rotary shaftadjacent to said adjustment nut for securing said rotary shaft to theseat tube of the bicycle, said clamp comprising a fixed jaw and amovable jaw pivotally connected to said rotary shaft, a locking pinpivotally connected to the free end of said fixed jaw, and an operatinghandle pivotally connected to the free end of said locking pin andoperable to secure the free end of said locking pin to the free end ofsaid movable jaw and to further lock said clamp to the seat tube of thebicycle.
 2. The power drive assistant system as claimed in claim 1,further comprising a clutch structure coupled between said rotary shaftand said clamp for allowing elevational adjustment of said rotary shaftrelative to said clamp, said clutch structure comprising a rectangularbar transversely disposed at a rear side of said clamp, a gear fixedlymounted on said rectangular bar, two spring members mounted in saidrotary shaft adjacent to said gear, two pawls respectively supported onsaid spring members for engaging said gear, a clutch lever pivotallyconnected to said rotary shaft, and a cam fixedly mounted on one end ofsaid lever between said pawls and movable by said clutch lever toselectively force said pawls away from said gear.